Facts about Contaminated (Dirty) Diesel Fuel

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1 Facts about Contaminated (Dirty) Diesel Fuel Source: ExxonMobil Contamination of fuel by water and dirt entering the fuel as a result of careless fuel handling may cause poor diesel engine performance. Extreme care must be exercised. Fuel-tank caps, dispensing nozzles and hoses should be kept clean to eliminate potential sources of contamination. Regularly removing water from storage tanks, vehicle fuel tanks, and filter bowls is important. Dry storage systems will reduce fuel emulsion problems, injection system corrosion and microbial growth. How does water get into diesel fuel and what problems can it cause? Water gets into diesel fuel storage and vehicle tanks in several ways by condensation of humid air, during transportation from refineries to service stations, by leakage through faulty fill pipes or vents and by careless handling. Water can cause injector nozzle and pump corrosion, microorganism growth and fuel filter plugging with materials resulting from the corrosion or microbial growth. Both vehicle and storage tanks should be checked frequently for water and drained or pumped out as necessary. In extreme cases, biocides may be required to control microorganism growth. In cold northern winters, ice formation in fuels containing water creates severe fuel line and filter plugging problems. Regularly removing the water is the most effective means of preventing this problem; however, small quantities of alcohol may be used on an emergency basis to prevent fuel line and filter freeze-ups. Cleanliness refers to the absence of water and particulate contamination. This characteristic is important because dirt and water can plug fuel filters in your engine and cause severe damage to your fuel injection system because of the close tolerances within fuel pumps and injectors. All diesel engine manufacturers equip their engines with fuel filters to protect the fuel delivery system. You should replace these filters according to the manufacturer's recommendations. Some manufacturers also provide filters with drain valves and recommend periodic draining of any water that may accumulate from condensation and careless handling in storage or vehicle tanks.

2 Water in a fuel storage tank can cause operational problems Tank maintenance is an essential part of any successful premium diesel or heating oil program. As little as.01% (100ppm) water in a fuel storage tank can cause operational problems. Water cannot be completely eliminated from distillate fuels. It can get into the fuel at various stages as it progresses through the distribution network from the refinery to the end-user. Water can get into the fuel during its production, when the hot fuel is in contact with process water. Most of this water is removed in the stripping units at the refinery and more will separate as the fuel cools, but still, some water remains in solution with the diesel. This entrained water may cause a haze in distillate fuel. Most of the water present in fuels will drop out as it is heavier than the fuel and will sink to the bottom if given time. The temperature of the fuel has an impact on its water-shedding tendencies as well. Warmer fuel can hold more water in suspension than can colder fuel. Water can also be introduced during transportation and storage of the fuel as well. Sea-going vessels can sometimes introduce water into distillate fuel, which can then drop out into storage tanks. Tanks themselves have inherent problems at roof seals and vent pipes which can allow rain water to seep into the system. During fuel withdrawals, tanks can breathe in large volumes of humid air. Moisture in the air will condense when the ambient temperature falls, collecting in tank bottoms. This is particularly prevalent in the spring and fall when the day-night temperature fluctuations can be extreme. Engine Issues due to Water (Hydrolock) Common damage modes include bent or broken connecting rods, a fractured crank, a fractured head, a fractured block, crankcase damage, damaged bearings, or any combination of these. - Examples #1 & #2 of Hydrolock Damage.

3 - Example #3 of Hydrolock Damage. - Paraffin Wax/ Gel build-up on a diesel fuel filter due to untreated diesel fuel in cold weather.

4 - Clogged Racor Fuel Filters on a 750kW Generator due to untreated fuel, algae, sediment, & tank deterioration. - Before (left), During (Center), & After (Right) Fuel Samples of a diesel fuel

5 - Dirty (Clogged) Fuel Polishing Filter that was used to extract algae & sediment from the bottom of the emergency generator diesel fuel belly tank near the engine s fuel pick-up tube. - Before and After Fuel Samples of a CFS Fuel Polishing Service. Please Note the Sediment and Algae Present at the Bottom of the Sample Bottle on the Left compared to the After Sample on the Right.